1. Field of the Invention
The present invention relates generally to radar motion detection, and more particularly to using a sparse array of time modulated ultra wideband radars for highly selective intrusion detection.
2. Related Art
Today, many homes and businesses employ surveillance systems for intrusion detection. Consumers have spent billions of dollars on home security systems over the last few years, and the number of homes with security systems has increased by almost half. These systems vary dramatically in sophistication and cost, but most include perimeter sensors on outside doors and windows, motion detectors in key inside areas, a control unit to interpret and respond to signals from the sensors, and a siren or other alert mechanism. Most are connected to a central monitoring station, which can notify the police in the event something triggers one of the sensors.
Conventional intrusion detection systems, particularly those in the cost range of the average home or small business owner, suffer from very high false alarm rates, often 90% and above. This imposes prohibitive costs on local police departments having to answer these false alarms. Many cities have responded by charging fines for answering these calls. This in turn provides incentive to home and business owners to deactivate the alarm system to avoid the false alarms. One study suggests that in burglarized homes with alarm systems, almost half of the alarms weren't even activated.
Conventional intrusion detection systems suffer a high rate of false alarms for many reasons. One reason is that these systems provide minimal selectivity. As used herein, selectivity refers to an intrusion detection system's ability to distinguish movement on some basis, such as where the movement is occurring, how fast an object is moving, or the path that an object is moving along. Obviously, detection systems that are more selective will likely suffer fewer false alarms because threatening movement can be more precisely defined and distinguished from movement defined as benign. What is defined as threatening and benign will vary by the particular environment in which the system operates. For instance, in a home environment, threatening movement could be defined as movement around the outside perimeter of the house, while movement inside the house is defined as benign. Therefore, an intruder approaching a door or window from the outside would trigger the alarm, whereas a child opening a bedroom door would not.
A need therefore exists for a highly selective intrusion detection system and method.